The present invention relates to a suspension and drive arrangement for a driven wheel of a motor vehicle, and more particularly to an independent rear suspension and drive system for a motor vehicle having one or more driven wheels.
Motor vehicles, including two-, three- or four-wheeled vehicles such as certain motorcycles and golf cars, automobiles and larger vehicles incorporating more wheels and wheel axles, are well known to comprise a vehicle frame, an engine mounted thereon, and a suspension and drive system for connecting wheels to the vehicle frame, for minimizing the effects of vibration and vertical displacement due to uneven driving surfaces without significantly impairing the vehicle""s handling, and generally for propelling the vehicle. Independent suspension systems in particular allow for the independent vertical displacement of a single wheel in relation to the other wheels.
Many two-wheeled chain-drive vehicles such as certain motorcycles are known to utilize swing- or trailing arms having a generally forked- or xe2x80x9cUxe2x80x9d-shape, to suspend the rear wheel. Such trailing arms generally incorporate a pivot shaft at the end opposite the wheel for connection to the balance of the suspension and drive system. Vertical displacement of the rear wheel causes the wheel to move in an arc about the pivot shaft axis or centerline. If the pivot shaft axis is offset even a relatively small amount from the transmission output shaft axis however, significant drive length variations may occur. Such variations generally lead to a rough or jumpy drive, and cause wild chain tension variation which ultimately results in drive system damage. Thus there have been several attempts to minimize or eliminate the offset between the trailing arm pivot shaft axis and the transmission output shaft axis in the area of motorcycle suspension and drive system design.
Despite the problems posed by these chain tension variations, trailing arms are attractive for smaller vehicles such as motorcycles because they are low cost in that environment, and they require very little space. In the area of larger, e.g., three- and four-wheeled vehicles such as golf cars, automobiles and trucks however, trailing arms are generally not utilized without additional support due to the high structural stresses presented by such an arrangement, the difficulty in maintaining appropriate camber and caster profiles, the difficulty in accessing the power transmission member for adjustment or replacement thereof, and the difficulty in accessing the tire for adjustment or replacement thereof.
Accordingly, it is a primary object of the present invention to provide a suspension and drive system for a motor vehicle, which utilizes a trailing arm as its primary support of the driven wheel or wheels.
It is a further object of the present invention to provide an independent rear suspension and drive system for a motor vehicle having at least one driven wheel, which utilizes a trailing arm as its primary support of the driven wheel, and wherein the pivot axis of the trailing arm and the rotational axis of the transmission output shaft are substantially coincident.
It is a yet further object of the present invention to provide an independent rear wheel suspension and drive system for a motor vehicle having at least one driven wheel, which utilizes a trailing arm as its primary support of the driven wheel, and which is economical and can bear both the wheel load of such vehicles as well as the high speed rotation of the transmission output shaft.
It is still another object of the present invention to provide an independent rear wheel suspension and drive system for a motor vehicle having at least two laterally opposed rear wheels, which allows for improved access to the drive system""s power transmitting member over known suspension and drive systems incorporating trailing arms.
To achieve the foregoing and other objects and in accordance with a purpose of the present invention as embodied and broadly described herein, a vehicle is provided comprising a vehicle frame; at least one drive wheel; a power source; a suspension and drive system connecting said at least one drive wheel to said frame and connecting said power source to said wheels; wherein the suspension and drive system comprises at least one trailing arm mounted on the vehicle frame and having a first end housing a pivot shaft and a second end operatively connected to one of the at least one wheel. The suspension and drive system furthermore comprises a power shaft transversely journaled in the vehicle frame; at least one power shaft output member operatively connected to the power shaft; at least one drive member operatively connected to one of the at least one wheels; and at least one power transmission member operatively connecting the at least one power shaft output member to the at least one drive member. The at least one pivot shaft is independent of the power shaft and the centerline of the power shaft is substantially coincident with the centerline of the at least one pivot shaft.
In a further embodiment of the present invention, a motor vehicle is provided comprising a vehicle frame, at least two laterally disposed wheels, a power source, a suspension and drive system connecting the wheels to the frame and connecting the power source to the wheels. The suspension and drive system comprises at least two trailing arms, each of which has a first end housing a pivot shaft which is journaled in the vehicle frame, and a second end operatively connected to one of the at least two wheels. The trailing arms are mounted on laterally opposed sides of the vehicle frame. The suspension and drive system further comprises a power shaft which is transversely journaled in the vehicle frame. The power shaft includes a differential, and at least two power shaft output members, the power shaft output members being located one each on either side of the differential. Each of the power shaft output members is operatively connected to a drive member, generally by means of a power transmitting member. Each of the drive member is in turn operatively connected to one of the vehicle""s wheels. Each of the trailing arm pivot shafts is independent of the power shaft. What is meant by the term, xe2x80x9cindependentxe2x80x9d in this context, is that the power shaft and the pivot shaft are not physically attached to one another; are in fact separate structures, but are operatively connected to one another by means of the power shaft output members, power transmitting members and drive members. The axis, i.e., centerline, of the power shaft is substantially coincident with the axis, i.e., the centerline, of each of the pivot shafts.